Field of the Invention
The present invention relates to an engine-driven working machine equipped with an outer case, and having an engine housed in an inside of the outer case.
Description of the Related Art
In an engine-driven working machine, cooling capability for a heating unit of an engine or the like influences performance. As the engine-driven working machine, there is known a generator in which an engine is housed in an outer case, a crankshaft of the engine is disposed along a lengthwise direction (that is, a longitudinal direction) of the outer case, and a cooling fan and a power generating unit are connected on an axis line of the crankshaft. Further, a muffler is provided in an axial direction of the crankshaft (refer to Japanese Patent Laid-Open No. 2005-133638, for example.).
The cooling fan, the power generating unit, the engine and the muffler are disposed on the axis line of the crankshaft, whereby it becomes possible to cause cooling air that is sent from the cooling fan to flow rectilinearly. Thereby, pressure loss of a cooling air passage that guides the cooling air can be decreased, and the cooling capability for the heating unit of the engine or the like can be secured.
Here, in the engine-driven working machine of Japanese Patent Laid-Open No. 2005-133638, the crankshaft is disposed along the lengthwise direction (that is, the longitudinal direction) of the outer case. Thereby, vibration occurs in a width direction of the engine-driven working machine, around the crankshaft, by driving the engine. In order to absorb the vibration in the width direction, the engine is supported by rubber support portions.
However, in the width direction of the engine-driven working machine, a width dimension is suppressed to be relatively small. Thereby, it is difficult to secure a large space in a width direction between the rubber support portions. Consequently, it is difficult to suppress the vibration of the engine-driven working machine by the rubber support portions, and this becomes a hindrance to enhancing merchantability of the engine-driven working machine.
Incidentally, some engines are equipped with overhead cam shaft (OHC) type valve operating structures (hereinafter, referred to as valve mechanisms). When the crankshaft of the engine is disposed along the longitudinal direction of the outer case, the intake valve and the exhaust valve are disposed in the width direction of the engine-driven working machine.
Consequently, when the carburetor and the air cleaner are disposed at the intake valve side, and the muffler is disposed at the exhaust valve side, the width dimension of the engine-driven working machine increases. Therefore, it is necessary to dispose the carburetor, the air cleaner and the muffler in a position where an influence on the width dimension of the engine-driven working machine can be decreased. Consequently, the intake passage and the exhaust passage are complicated, flow resistances of the intake air and exhaust gas that flow in the respective passages increase, and inhibit securing of the output power of the engine.